Some woods used in the making of acoustic guitars.
Listed in alphabetical order not in the order of popularity.

BASSWOOD - Sometimes used for inside linings.
EBONY - Preferred wood for bridges & fretboards on steel string guitars,
ROSEWOOD is also good and sometimes preferred for bridges on nylon
string guitars.
CEDAR - A wood softer than spruce used for tops on steel string and classical
guitars. Some guitarists prefer this wood for its new guitar tone but
some luthiers don't like to work with it on repair jobs because of its
soft nature.
CHERRY - Sometimes used for backs and sides.
COCOBOLO - Rosewood from Central America and Mexico.
CYPRESS - Used on the backs and sides of flamenco guitars only.
KOA - Midrange sounding wood from Hawaii used on some guitars for back,
sides, and tops.
MAHOGANY - Preferred for necks. Also good for backs, sides, inside bracings
and sometimes tops.
MAPLE - Sometimes used for backs and sides on larger guitars. Wood of choice
for f-hole guitar bodies. Sometimes used for bridge plates.
NATO - Used as a substitute for MAHOGANY on necks and sometimes bodies of less
expensive guitars. It is less stable than MAHOGANY.
OVANKOL - A ROSEWOOD substitute with qualities somewhere between ROSEWOOD and
MAHOGANY.
PEAR - Used for bindings. Treated PEAR is sometimes used as a substitute for
EBONY fingerboards on less expensive guitars.
PINE - Unfortunately sometimes is used on less expensive guitars for inside
linings, end blocks, and heel blocks.
REDWOOD - Somewhat similar to cedar, used more on classical guitars.
ROSEWOOD - Sometimes the most desirable wood used for backs and sides on classical
and steel string flattop guitars although MAHOGANY and MAPLE are also
very good on the latter. Also used for bridgeplates, bridges and
fretboards.
SAPELE - Less expensive than mahogany but a good tonewood none the less with a
little brighter sound.
SPRUCE - There are a lot of different kinds of SPRUCE that are used in the making
of acoustic guitars and SPRUCE is usually the wood of choice for the
front (or top, sound board) of the guitar. Sometimes, it's also used for
the bracing under the soundboard. Unless it's an expensive guitar, the
manufacturer probably won't even mention the type of SPRUCE it is.
German (or European) SPRUCE can be from various countries in Europe and
this is sometimes reguarded as the best.
Engelmann (or Englemann) SPRUCE from the US is usually used on expensive
models along with Sitka, and Adirondack SPRUCE also grown in the US maybe
Canada. When picking out a guitar, look at the top. If the guitar has
a natural finish, the wood should be a light color. There shouldn't be
a large difference in shade between the wood and grain, and the grain
should be from 12-15 per inch minimum.
WALNUT - Used for bindings. Sometimes fronts, backs, & sides. Treated WALNUT is
sometimes used as a substitute for EBONY fingerboards on less expensive
guitars. Also sometimes used for bridges.